1. Field of the Invention
The present invention concerns an x-ray tube of the type having a rotary anode that rotates on a rigid shaft.
2. Description of the Prior Art
An x-ray tube of the above type is known from Japanese Application 3228992. In this known x-ray tube, an node plate Is attached to the closed end of an anode tube via a short, rigid axle. The anode tube is mounted on the rigid axle such that it can rotate. In the area of the end of anode tube, a fluid metal is incorporated for improving heat dissipation from the anode plate. Although, the heat transfer from such an anode plate to a cooling device incorporated into the anode axle is improved, in the manner a further improvement of the cooling of the anode plate would be desirable to improve the overall performance of such an x-ray tube.
Rotary piston radiators are known from German OS 197 41 750, German PS 198 51 853 as well as German OS 199 56 491 wherein a rotary drum surrounding an anode plate is incorporated in a rotatable fashion in a housing. Located between an inner surface of the housing and an outer surface of the rotary piston is a liquid coolant that circulates around the rotary piston to dissipate heat. Rotary piston radiators have the advantage that large amounts of heat can be removed. The high performance drive needed for the rotary piston is, however, disadvantageous.
European Application 1 047 100 discloses an x-ray tube in which an anode plate is mounted onto a rigid hollow anode axle such that it can rotate. The anode plate is hollow in sections thereof and liquid coolant flows through it for heat dissipation. The coolant is supplied and removed via the hollow anode axle. This x-ray tube is complicated in terms of design and therefore expensive to manufacture.
German PS 36 44 719 describes a liquid-cooled x-ray tube. A cylindrically designed rotary anode is mounted to rotate around a cooler. The cooler in turn encloses, as an annular channel, a rotatably supported anode axle connected with the rotary anode. A liquid metal for improving heat dissipation is disposed between an outer surface of the cooler and an inner surface of the rotary anode.
U.S. Pat. No. 4,577,340 describes an x-ray tube in which an anode plate is firmly connected with a hollow anode axle. The anode plate is partially hollow and is supplied with liquid coolant via the anode axle. Additional x-ray tubes with hollow liquid-cooled anode plates are known, for example, from European Application 0 576 258 as well as European Application 0 330 336. X-ray tubes with hollow anode plates generally require a high manufacturing expenditure,